1. Field of the Invention
The present invention relates to a golf club with a shaft connected to one side of a head comprising a hollow body formed by combining a plurality of metallic shells.
2. Description of the Related Art
Heretofore, it is well recognized that a xcex2 type titanium alloy has been used as a raw material for a face portion of a golf club head. The xcex2 type titanium alloy is easy to process by cold plastic forming as compared with other titanium alloys, particularly suited for press molding something from plate raw materials. Further, the xcex2 type titanium alloy has an advantageous characteristic that sufficiently high strength can be obtained by subjecting the same to heat treatment.
In the xcex2 type titanium alloy, however, the heat treatment may have the opposite effect of reducing inherent properties of a raw material depending on the composition thereof. For example, whilst well-known Ti-15V-3Cr-3Sn-3Al (hereinafter referred to as Ti15-3-3-3) has its strength enhanced by heat treatment, Ti-15Mo-5Zr-3Al (hereinafter referred to as Ti15-5-3), although it also has its strength enhanced by heat treatment, has resultant decreased ductility or toughness so that it becomes apt to be cracked by repeated strikes by balls. Consequently, as Ti15-5-3 has such sufficiently high strength without heat treatment, it is usually used without heat treatment.
In the manufacturing process of golf club heads, heat treatment is typically performed after assembling a head by welding and then shaping it by grinding or the like. At the time of welding, the welding heat causes changes in the tissues of the materials in welded portions, causing non-uniformity in tissues between the welded portions of the head and the remaining portions thereof, which, however, can be made uniform by post heat treatment.
However, when using the aforesaid Ti15-5-3 or the like which preferably should avoid heat treatment from the point of view of strength, differences in tissues between portions affected by welding heat and those around them remain as they are. In this case, the welded portions are subjected to changes in the tissues by the welding heat, thus resulting in the decrease in toughness. As a result, there occurs a problem that the welded portions are apt to be cracked by the repeated strikes by balls.
To eliminate the above problems, it is, therefore, an object of the present invention to provide a golf club which has a sufficiently high strength in welded portions even if materials which should preferably avoid heat treatment are used.
A first aspect of the present invention is a golf club with a shaft connected to one side of a head comprising a hollow body formed by joining a plurality of metallic shells including a face member provided with a ball-striking portion on a front face thereof, in which a reinforcing plate is provided on a portion where the face member is joined to a sole portion of the head.
According to the construction of the first aspect, as the reinforcing plate is provided on the portion where the face member is joined to the sole portion of the head, even if a certain material whose tissues change due to the influence by the welding heat so that it decreases its toughness is used, sufficiently high strength can be insured on the welded portion between the face member and the sole portion of the head.
A second aspect of the present invention is a golf club according to the first aspect, in which the head is not heat-treated after the welding.
According to the construction of the second aspect, costs incurred by heat treatment can be eliminated due to no heat treatment being performed after welding, so that a golf club can be provided at low cost.